LOS ANGELES (CBS) — A man federal authorities call “a major wildlife trafficker” was sentenced Monday to 21 months in federal prison for smuggling 55 live turtles and tortoises inside snack food boxes into the United States last year.

Yamagami pleaded guilty to smuggling the 55 reptiles from Japan in August. Most of the smuggled animals were species protected by the Convention on International Trade in Endangered Species.

Federal prosecutors had also argued that the method of cramming the turtles into snack food packages, that were then stuffed into suitcases, constituted animal cruelty and that the animals posed the risk of transmitting salmonella.

Since his arrest at Los Angeles International Airport in January 2011, Yamagami has been held without bail.

Federal agents say Yamagami was the leader of an organized group of Japanese nationals responsible for smuggling protected turtles, tortoises, chameleons and lizards into and out of the U.S., primarily through airports in Honolulu and Los Angeles. After smuggling them into the country, Yamagami would sell or trade them at reptile shows across the U.S., using the proceeds to buy snakes, turtles and tortoises native to North America, prosecutors said.

An investigation determined that between 2004 and 2011, Yamagami and his couriers took 42 trips to and from the U.S., according to federal agents.

Norihide Ushirozako and Hiroki Uetsuki, two of Yamagami’s couriers from Osaka, were arrested and prosecuted for wildlife smuggling in 2011. Ushirozako was sentenced in August to time served — approximately seven months — and Uetsuki was also sentenced to time served, approximately six months.